The babies who watched the video with a parent didn’t do terribly worse, but they definitely didn’t learn more. The clear implication is that infants learn best from live interactions with their parents. Other studies have found that smart baby videos actually seem to slow language development. So why do so many parents buy smart baby videos if they don’t do what they promise? Possibly because the companies that make them are good at marketing their products to parents willing to spend money on anything claiming to make their kids smarter. But scientifically speaking, those parents are better off saving their money and spending more time with their kids.